Lamp structure



Jan. 6, 1948. n y c. w. cLARKsoN, JR., a-r All A 2,433,982

' LAMP kSTRUCTURE:

Filed hat. l27. 1944 3 wenrow Clarence d'.CZcbrlnSO-nl,v n #Edward J. l1rok f u #gk w v l y Cltroz'ueljs Patented Jan. 6, 1948 LAMrsTRUcTUREClarencew. jClarlrson, Jr.,i Washington, D. C., and-EdwardJ. Krek,Chicago, Ill.

' ApplicationV October 27, 1344, Serial No. 560,612

` 1 This invention relates to lamp structures, and more particularly tothose which are used in surgery, although not limited thereto.

Generally stated, surgical lamps are designed to produce on a restrictedoperating eld a beam of light which is shadowless, intense yet cool, andat the same time color-corrective. In the case of a wound, it isparticularly important that besides being cool the restricted beam o'flight be not only shadowless but possess natural color characteristics.as otherwise proper diagnosis is very diiiicult. The properilluminationv of'rdepth is best obtained lby a light beam derived frommultiple sources; and itis therefore most expedient to employ multipleunitsl each of which can be adjusted both physically and optically totrain their respective projected light rays upon the focal object.

Numerous prior art lamp structures have sought to attain the foregoingobjectives, but, so far as we are aware, they are all possessed of oneor more shortcomings, among which are expensiveness to manufacture andmaintain, diinculty of operation, and excessive bulk.

It is among the objects of the present invention to provide acomparatively simple and efiicient illuminating apparatus, particularlyof the type used in surgery, which projects al light beam of restrictedcross-sectional area and which is intense yet cool, practicallyshadowless, and possessed of substantially natural color.

Another object is the provision of a compact structure of the classdescribed which 'is easilyI portable and vreadily adjustable to projectthe desired type of light beam in almost any direction.

The invention, then, comprises the features hereinafter fully described,and as particularly pointed out in the claim, the following descriptionand the annexed drawing setting.'v forth in detail a certainlillustrative embodiment of the invention, this being indicative of butone of a number of ways in which the principle of the invention may beemployed.

In said drawing:

Figure 1 is a sectional elevation of the lamp structure of Vtheinvention.

FigureZ is a fragmentary plan.

Referring more particularly to the drawings, the numeral 2 designates alarge conical reflector of standard design, the same being made ofeither metal or glass in the manner well known in the art. At its inner.or reduced, end the conical reilector 2 is provided with a short annularflange 3 depending froman annular flange 3', which is Y 1 Claim. -(Cl.Z740-1.4:)` y

2 y substantially at right angles to a somewhat longer annular sleeve,and at its outer or enlarged end, the conical reilector is provided withan annular shoulder 23 and a depending side wall 26.

Disposed within the conical reflector 2 is an annular Fresnel lens 5- ofstandard design`the same being supported in position by means of aseries of screws 6 which extend radially inward through the shortannular flange 3 and grip the said lens at spaced peripheral pointsadjacent its inner end.' y

As is well known to those skilled in the art of illumination, a Fresnellens may be -regarded as a plurality of lenses, the curvature of theback surface of each lzoney being so chosen as to eliminate .sphericalaberration. This construction can be modified to distribute light inalmost any desired manner. In the embodiment shown, the annular lens 5has a cylindrical bore and the exterior of the said lens is shaped toprovide the Fresnel lens elements, the same being designated at 5a.

Disposed within the annular sleeve 4 is a light bulbA socket I which issupported by an adjusting vmechanism generally indicated at 9. Theadjusting mechanism 9 is provided with an operating thumb-screw 9a which"is disposed exteriorly of the annular sleeve 4, the same being operableto adjust the bulb socket 'I longitudinally of the said annular sleeve.The thumbscrew 9a is mounted on the outer end of 4a transverselyextending shaft I4 rotatably mounted in bearing members I5 provided onthe annular reflector sleeve 4. The shaft I4 has a pinion I'S i mountedthereon adjacent to the inner end of the shaft, which pinion meshes witha rack I I provided on the light socket housing I8, which rack I1 tsinto a slot I9 formed in the reector sleeve 4.

The bulb socket 'I carries a light bulb I0 which f projectsinto theannular-Fresnel lens 5. For the purposes of a surgical lamp the lightbulb i0 may suitably be any one of a number of concentrated lfilamenttypes, the same as such form ling no part of the present invention.

The outer' end of the annular Fresnel lens 5 is provided with alight-impregnable closure I I which may suitably take the form of aconcave- Vconvex cap vprovided with a continuous radially of theadjacent end of the annular lens l, and held in position therein by aseries of screwsl2.

According'to the foregoing construction and arrangement each of thelight rays emitted by the light bulb l must, in order to be projectedfrom `the outer end of the conical reflector 2, travel through theannular Fresnel lens 5. In this manner, then, the light rays transmittedto the conical reflector 2 are directed by the latter to a point ofconcentration which is coincident with the axis thereof. In addition,the point of concentration may be varied by the simple expedient ofadjusting the longitudinal position of the light bulb .8 withrespect tothe annular Fresnel lens 5.

When the light bulb is raised by means of the adjusting mechanism 9 thelight rays passing through the lens 1 are bent down and are concentratedat a lower point than was the case prior to said adiustment, but on thesame axis. When the light bulb vIl! is lowered, the converse is true (i.e. the light beams concentrate at a higher point out on the same axis asaforesaid). Whatever the degree of adjustment, the reflected light beamis in effect the same as.derived from multiple sources because of theoptical effect of the combined annular Fresnel lens and the conicalreflector 2. Thus, the projected light beam is inherently shadowless.

The outer end of the conical reflector 2 is provided with a conventionalheat-absorbing and color-corrective glass I3 which is suitably removablymaintained in position by spring clips 20 mounted in an annular closuremember 22 for the outer or enlarged end of the conical reflector, theclosure member 22 being connected hingedly on the side wall 26 of thereector by the hinge 25. The closure member 22, when in closingposition,abuts against the annular shoulder 23 on the reflector 2 and isheld removably in position by screw 24 threadedly mounted in the sidewall 26 and contacting the closure member 22 at its inner end indiametrically opposite relation to the hinge 25. Upon loosening thescrew 24, the closure member 22 may be swung open about its hinge 25 forreplacing or cleaning the parts of the lamp structure. The effect of theglass I3 is to intercept the light rays projected by the con-l icalreiiector and remove therefrom the heat-giving infra-red rays and alsoany color characteristics, whereby the proiected beam of light isrendered cool and colorless.

Other modes of applying the principles of the invention may be employed,changes being made as regardsthe details described, providing thefeatures stated in the following claim, or the equivalent of such, beemployed. l

Having thus described our invention, what we claim as new and wish tosecure by Letters Patent is:

A lamp structure comprising a reiiector housing havin-g a cylindricalsleeve portion and a conical reflector portion, a cylindrical housingadjustably mounted in the sleeve; an annular flange extending from thesleeve portion at substantially right angles thereto, and a secondflange depending substantially perpendicularly therefrom, the conicalreflector portion extending divergingly from the second ange, means forslidably adjusting the housing in the sleeve, a light socket mounted inthe housing, a lamp mounted in the socket, a tubular Fresnel lensenclosing the lamp, a series of screws threadedly mounted in the secondflange and extending therethrough in engagement with the Fresnel lensfor holding the lens in position, an opaque cap closing the lens, meansfor securing the cap to the lens, the said conical reiiector portionterminating in an annular shoulder having a flange depending therefromto form an annular wall, an annular closure member for the conicalreflector positioned in the wall, a heat-absorbing and col-'or-corrective glass removably mounted in the arinular closure memberfor closing the annulus thereof, a connection between the annularclosure member and the wall, and a securing screw threadedly mounted inthe wall and extending therethrough in engagement with the annularclosure member in diametrically opposite relation to the said connectionfor holding the closure member in closing position against the shoulder`for closing the conical reiiector portion.

CLARENCE W. CLARKSON, JR. EDWARD J. KROK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Great Britain Jan. 8, 1942

